ISTC researchers were awarded three patents recently for inventing more sustainable industrial processes. Kishore Rajagopalan, associate director and Illinois' State Pollution Prevention Scientist, along with Vinod Patel, manufacturing engineer, developed a method for recovering solvents (including water) from solution by using a polymer to create osmotic pressure. The process allows recycling of both the polymer and the solvents. The concept has already been applied to a low-energy product for desalinating drinking water in disaster zones called Aquapod.
For the other two patents, B.K. Sharma, senior research engineer at ISTC, and colleagues at the U.S. Department of Agriculture's National Center for Agricultural Utilization Research and Agricultural Research Service demonstrated the production of industrial lubricants based on vegetable oil instead of petroleum.
"These innovations fulfill a core mission of ISTC's research efforts by finding ways to use less water, less energy, and cut toxics use in favor of renewable alternatives for sustainable industry," said Rajagopalan, who oversees ISTC's research portfolio. "If they lead to new high-value uses for waste water and agricultural products, that is all the better," he added.
Aquapod is one example of ISTC's advancement in forward osmosis that promotes the separation of solvents from a variety of industrial processes. Filtration by forward osmosis is inexpensive but slow. Filtration by reverse osmosis, while faster, uses much more energy and harsh by-products which are disposed of in waste water. The patented Aquapod process introduces a non-toxic, non-corrosive polymer to raise the osmotic pressure and speed separation. The polymer itself is easily recovered and reused, reducing costs further.
At this stage in its development, the method appears most applicable to medium- or small-sized desalinization units which can easily be deployed to disaster areas where fresh water is critical, said Rajagopalan. Large semi-permeable membranes are being constructed in ISTC labs to investigate additional scale-up potential.
For their processes that were awarded patents, Sharma and his team demonstrated easy and environmentally friendly reactions which can cost effectively produce green, renewable and biodegradable replacements for conventional petroleum-based products. The team developed methods for adding phosphorus and nitrogen to the molecular structure of the triglyceride (vegetable) lubricants.
Vegetable oils are readily biodegradable, easy to handle, environmentally friendly, non-toxic fluids that are also readily renewable resources. But natural vegetable oil suffers from poor thermal/oxidation stability which makes it unsuitable for industrial machinery.
The active ingredients in mineral oil-based commercial anti-wear/anti friction additives include phosphorus and nitrogen (as well as sulfur and zinc).
Soybean oil is the ideal raw material in the process because it is readily available and inexpensive. Many other agricultural products also work well, such as cottonseed, corn, olive, peanut, palm, sesame, sunflower, canola, castor, safflower, linseed, grape seed, oiticia, tung, rice, crambe, high erucic rape, algae oils, animal fat, and high oleic canola oils.
In the case of the phosphorous-added lubricants, unsaturated fatty acids in the plant oil are converted to epoxides and reacted with phosphorus-based acid hydroxide or ester reactants to produce methylene derivatives.
Sharma has studied the pyrolysis of agricultural materials and various commonly landfilled wastes, such as hard to recycle plastics, to search for high-value industrial products and additives. The nitrogen- and phosphorous-containing triglyceride derivatives produced biodegradable lubricants which had superior properties for use as crankcase oils, transmission fluids, two-cycle engine oils, marine engine oils, greases, hydraulic fluids, drilling fluids, metal cutting oils, and the like.
The team predicts that the derivatives will prove valuable when mixed with other additives such as detergents, anti-wear agents, antioxidants, viscosity index adjusters, pour point depressants, corrosion protectors, friction coefficient modifiers, and colorants.